Video conferencing is an established method of collaboration between remotely located participants. A video image of a remote environment is broadcast onto a local display allowing one or more participants at a local site to see and talk to one or more remotely located participants.
Some videoconferencing applications seek to provide physically realistic eye contact between participants at remote sites. This can be referred to as “person-accurate”, or “personalized”, eye contact. For a two-person videoconference, this can be accomplished by orienting the camera viewing a local participant at each site to view him from the direction at which the remote participant is displayed to the local one. For a three-person video conference, where each participant is at a different site, accurate eye contact is achieved by using two cameras at each site, and having them directed toward the local participant from the directions at which the remote participants are displayed. The view sent to each remote participant should be that from the camera oriented along the direction at which that remote participant is displayed to the local user.
In general, for any number of N participants at N sites, N−1 cameras may be used at each site and positioned around the local participant to capture images of the local participant. These images of the local participant are taken from correct viewpoints of the N−1 remote participants. These images are then sent to each remote participant providing a view of the local participant from the direction at which that remote participant is displayed to the local one.
A disadvantage of these video conferencing systems is that they require a different number of cameras for each choice of N. Also, as N increases, it requires more and more remote participants to be displayed to the local one, such that many display systems will produce reasonable representations of the remote participants for only a limited range of N. Finally, if the number of participants at a given site is greater than one, it is no longer possible to maintain accurate eye contact for each participant unless unconventional displays are used. Specifically, either costly three-dimensional displays, or displays showing different images to different viewing directions, would be needed.
Moreover, as the number of parties in multi-party videoconference change, videoconferencing systems that make some attempt to provide eye contact between remote participants require the reconfiguration of the physical equipment needed for capture. That is, videoconferencing systems that attempt to maintain “person-accurate” eye contact do not allow for scaling up or down the number of participants in a video-conferencing session, or changing the number of participants from one video conferencing session to the next, without physically changing or reconfiguring the equipment needed for capture and display.
Therefore, prior art methods of video conferencing were unable to satisfactorily provide for supporting an increasing number of parties in a video conference without physical reconfiguration of the capture and/or display hardware. Also, techniques of video conferencing were unable to satisfactorily provide adequate eye contact between remotely located participants, especially as the number of participants at each site number more than one.